Previously Unknown
by KageMori
Summary: A new timeline, a new creature comes to the underground. Something no one knew existed. The appearance of this creature changes everything. Dark secrets about humanity come to light. Once the barrier is broken...will the monsters even want to leave? Tragedy, horror, love, all combine. Mentions of torture and abuse. Papyrus/OC Sans/Frisk
1. Prologue

**This is my first ever story for the Undertale series. Im writing this more for my enjoyment than anything else, however I do hope you all enjoy it too.  
I apologize in advance for any spelling or grammar errors. Grammar is not my strongest point and I only have spellcheck to help me catch spelling errors.**

**If you find any errors that are bothersome that I miss please let me know and i'll do my best to correct them.**

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**Prologue:**

In ancient times there were two races that ruled the above ground together. They were the Humans, and the Monsters.  
Monsters were creatures created by pure magic and came in a variety of shapes and sizes. Most of these creatures were good and kind and only wanted to exist in peace with the humans.

Humans on the other hand were not, they were the opposite of monsters in every way. Most of them were greedy and selfish and consumed by their jealousy of the powers that monsters possessed wanted to wage war against them, in an effort to steal that magic for themselves.

So under the guise of only seeking to protect others from the evil magics of the monsters the human rulers waged a long and bloody battle against the monsters that lasted for years and years.

During this war many innocent monsters were captured and taken far away to a hidden place to be experimented on by human mages in an effort to steal their power for themselves.

Many of these captured monsters died terrible deaths. They were the lucky ones. Those that didn't die and turn to dust and their magic harvested from their souls and twisted and corrupted until nothing remained of the pure magic that it once held. This corrupted magic was then placed into human vessels to be further experimented on.

These "vessels" were then changed by the magic forced inside of them. Their bodies twisted and burned, consumed by the foreign magic. Bodies were torn apart, destroyed from the inside out as the magic burned away at them. Others melted into larges pools of goo, some even exploded.

As the experiments continued the war began to slowly come to an end as monsters were forced further and further underground, or into hiding. The royals and mages began to despair that they would never be able to harness the monster's magic for their own...until, success.

Some vessels, few that they were, began to survive the injections of magic. Their bodies were changed, some almost unrecognizable as former humans, but they were alive. More importantly, they were sane and appeared to be stable in both mind and body.

These surviving vessels then underwent more study and more experiments to learn to control the new magics and figure out how much their bodies had changed. And that's when the horrible truth was found. These surviving vessels required the blood and flesh of other humans to continue living.

Many became consumed by thirst and hunger and started attacking the mages. When the royals found out what became of the vessels and the death of the mages they ordered the studies shut down and the vessels destroyed.

All monsters were to be sealed away underground where their magic could never corrupt another human. The royals would rather live without the monster's powers than to suffer the same fate as the vessels.

And so it was the Monster/Human war came to an end and the hideous dirty truth behind it hidden away. Never to be seen by the light of day...or so they thought.


	2. Ch1 The Fall

**Chapter 1:**

It was a dark cold, cloudless night. The stars twinkled and shined brightly in the night sky. It would have been a beautiful view were it not for the current situation.

Twigs snapping, bushes breaking as the small slender figure ran at a quick pace. Pushing herself as hard and as fast as she could, willing her body farther, faster, beyond its limits to get away from the ones chasing her.

Thick pink curls flew behind her as she ran, her lungs burning and aching as she continued onward cursing herself for being so careless as to allow herself to fall into this trap. 'Almost there, just a little more!' she yelled inside her mind.

Up and up, higher and higher she ran. Dodging grasping arms and tossed ropes and traps until she was successfully up the top of the hill, to steep for any horses to follow. But she didn't let up, she kept up her quick pace and ran inside the nearby cave.

It wasn't until she was safely hidden inside that she finally allowed herself to slow down and stop. She knew that these men would not follow her here. Fear and superstitions outweighed their desire to capture her. Still, just to be on the safe side, she took herself even deeper into the cave.

Darker and darker it got, as she walked. She couldn't even see an arms length in front of her. Not for the first time tonight she cursed herself for her current predicament, She was to weak now. Easy prey for her enemies, and there were many.

Before she knew it she let out a loud yelp as she fell, expecting to hit the hard rock floor of the cave, her heart lept up to her throat as she realized she was still falling. Her life flashed before her eyes. 'This is it' she thought 'I die not by their hands, but by falling down a large hole!' The irony was not lost on her as she shut her eyes and prepared her self for death as she finally hit the ground with a sickening crunch.


	3. Ch2 Meeting Toriel

**Chapter 2**

An unknown amount of time passed before the pain set in. The throbbing in her skull pounded like a drum behind her closed eyelids. At least she hoped they were closed, the thought of being blind wasn't exactly a pleasant one. A particularly painful throb assaulted her as someone placed a cool wet rag to the back of her head and she hissed loudly and groaned.

A hand hovered over her injury for a moment before touching her again, softer this time. She moved to push the offending arm away but her limbs felt so weak she could do naught but groan again. "Im sorry child, I know it hurts, but the wound must cleaned." The voice was soft and gentle, reminding her of a mothers voice. They also held a hint of sadness in them.

She turned her head and struggled to open her eyes, when finally the cracked open the bright light of the room caused her to hiss again and close her eyes once more. "W-where am I?" She rasped out before forcing her eyes open once more.

She saw a tall creature dimming the light of the room and for that she was thankful as the pain lessened a bit. When the creature turned back to face her she gasped in shock and surprise as a giant goat woman stood across from her and was walking back toward her.

She was to weak to move and knew she could not run away. "Please don't be frightend child. I do not mean you any harm." She spoke, her voice was so soft and gentle. She held so much care and concern inside of her that she felt she had no choice but to relax and let the goat creature tend to her wounds. "As for where you are, your underground."

"Underground?" Her voice still a raspy whisper. The goat woman helped left her head slightly as she held a cup to her mouth. She took a few small sips of water and let out a sigh of relief as the water soothed her dry throat.

The creature nodded, "You fell from the surface world and landed here. I found you unconscious and injured. Your lucky I found her when I did, or else you would have died." She said nothing in response to that statement. "My name is Toriel, I am the keeper of the ruins, what is your name child?" She looked back at the goat woman, "Lizette, Lizette Hartford." Toriel nodded, "Well Lizette, now that you are conscious, if you wish I can use magic to heal you. We monsters have magic food and drinks that restore HP."

She chewed her lip, she wasn't sure how magic food would react with her, but Toriel seemed to think it was fine, so maybe it was? It was far better than being weak and bed ridden. "Yes please, Toriel." She smiled and helped her sit up, she placed one arm beneath her legs and the other around her waist before lifting her up bridal style.

Lizette blushed from embarrassment but said nothing as she was carried out the room and down the hall. She was led to the dining room and placed in a chair and scooted closer to the table. "I'll be right back child." Toriel walked away as the pink haired girl studied her surroundings. The home felt so warm and comforting and inviting. She cant remember the last time she felt so safe and at peace somewhere. She almost didn't want to leave. Almost.

A moment later Toriel walked back in carrying two slices of pie. It smelled good for what it was, but was not her cup of tea. However, not wanting to be rude she smiled and thanked Toriel for the pie. "Your welcome child. Eat up and the magic will heal you and restore you HP." She picked up the fork and took a bite of the pie. Butterscotch and cinnamon exploded in her mouth. It was quite good for a pie. "Its delicious Toriel."

She smiled brightly at her, "Im so glad you like it my child. Its my favorite and I make it quite frequently, well my favorite next to snail pie anyways." She blinked at her 'snail pie?' She shook the disturbing thought from her mind as she continued to eat her pie. By the time it was all gone she felt a hundred times better and more refreshed. She let out a sigh of relief, she still didn't completely feel like herself again yet, but she felt worlds better.

She picked the plate up as she made to walk away and wash it up. Toriel stopped her and shook her head. "Don't worry about it. I'll take care of it. Why don't you go wash up instead. After all you are still covered in dirt and blood, and your clothes need washed and repaired." She looked down at herself and couldn't help but agree.

"Do you remember the way." She nodded "Thank you, I appreciate everything that your doing for me." Toriel's smile brightened "Its nothing child, please go wash up. I'll bring you something to sleep in before collecting your clothes."

Lizette gave her a small smile of her own and left to go take a shower.


	4. Ch3 The warmth of Fire

**Chapter 3**

Lizette stood under the hot steaming water running her fingers through her long thick curly hair. Washing away the dirt and debris. Her mind was lost in thought, wondering, not for the first time how she found herself in this position.

She was god knows how far underground after being chased by knights and hunters from the old world, she was weak and helpless with no way to defend herself, and even at this very moment she could still feel the poison flowing thru her veins.

The poison that started this whole mess in the first place. To bad the monster food couldn't cure her of that ailment. She knew it was foolish to hope that it would. Only time can purge her body of its effect.

"Stupid, stupid stupid. How could you let your guard down like that!" She quietly cursed herself before turning off the water and stepping out of the shower. She walked over to the mirror and wiped away the fog to stare at her reflection.

Her curls were wet and clinging to her, her lightly tanned skin was covered in a dusting of freckles and chocolate brown eyes stared back at her. She was pretty average as far as humans go, at least she thought so, then again that was the point. She really didn't want to stand out anymore than she already did with her bright pink hair.

Luckily in this day and age, not many people paid attention to brightly colored hair, as no matter what she tried it was the one trademark she could never conceal.

She dried off, brushed her hair, and got dressed in the pajamas Toriel left for her. They were a little small but otherwise comfortable. She walked back to the living room to see Toriel with a pair of old fashioned square framed glasses on her face, sewing the rips and tears in her old outfit. She smiled at the motherly image before her. She gently cleared her throat to get her attention. Toriel smiled and motioned for her to come in.

Lizette came in and sat on the floor near the fire as Toriel continued to repair her clothes. "Im sorry those are so small, but it'll have to do for now until I can get you some more." She frowned, it seemed as though Toriel expected her to stay here. "Its alright, they're fine." "Well in any case the tears to your old outfit aren't that bad. After this i'll be able to wash them all up for you and they'll be good as new."

"Thank you for all your help Toriel. You didn't have to do half of what you've done for me, and I really appreciate it." "It's not problem at all my child, think nothing of it. I only wish I could do more for you."

She turned her head to look at Toriel. The sadness was seeping through again. She looked so old and so lonely. You wanted to question her but you knew your questions would be to personal and you didn't want to pry. But there was one question you just had to ask. "Toriel, why are you here, alone? Most guards of places have team members and others to help with tasks, why don't you?"

She looked surprised by your questions and a sad smile came on her face. "That's because this is not and official task. Im here by my own choice to watch for humans that fall into the underground. Usually, its children that have fallen down in the past. You're the first adult you know. I know its foolish to hope, but I do hope you'll stay here. The underground is not a safe place for humans. Not anymore."

"Why not?" She grew silent and stopped sewing, you could see the wheels in her mind turning as she went back in time. Unpleasant memories to be sure. "Years ago monsters were locked away underground and we are kept here by a barrier. Human souls are needed to break the barrier, thus the king has declared war on the humans and any human that falls into the underground is to be killed and their soul taken to break the barrier."

Lizette absorbed this information and filed it away for later, she sighed and looked back into the fire. Its pleasant heat warming her body as she wiggled her toes. "You are right, I cant stay here. As much as I would like to, I just cant." She doesn't want to involve Toriel in her problems. Its a long shot but there was always the chance that her enemies could find her here and she doesn't want Toriel getting hurt because of her.

"I understand my child, im sure you have a life and a family back on the surface that you need to get back to. Also you are an adult and I can not force you to stay here against your will." She holds Lizette's newly repaired clothes up before placing them across her arm and standing. "I suggest getting a good nights rest, if you plan to leave tomorrow you'll have a long journey ahead of you." She walked away, her posture heavy with sorrow. Lizette wished she could do something to comfort her, but she couldn't stay. She watched the flames of the fire flicker for what felt like hours before her eyes began to droop. Before she knew it she had fallen asleep curled up in front of the fireplace.


	5. Ch4 Farewell and Hello

**Chapter 4**

Lizette awakens early the next morning to a gentle shaking on her shoulder. Confused and disoriented she shot up swinging her arm out to hit whoever was touching her. Toriel gasps in surprised but is unharmed. Once it dawns on her what she's done she begins to apologize. "Oh! Toriel im sorry, so so sorry!"

Toriel laughs off her apology, "No worries my child, I didn't mean to startle you." Lizette stands and stretches, cracking her back in a most satisfying way. "Your clothes are all clean and ready for you." She says handing Lizette the stack of freshly folded laundry. She thanks Toriel and leaves to go change.

Her outfit is simple and average. Meant to help her blend in, again, despite her brightly colored hair. It was a simple pair of dark, almost black denim jeans and a dark red button up with 3/4 sleeves that end just below her elbow and a pair of brown work boots. She feels better and more comfortable in her clothes, though she knows that something is still missing from her attire, nothing that was Toriel's fault, merely her own carelessness.

She sighs and brushes her hair and teeth before going back down stairs to have breakfast.

"So I take you plan to leave now?" She nods as she eats, "There is nothing I can say or do to convince you to stay?" "Im afraid not, I have to go." Toriel nodded "I thought as much." She instructs Lizette on how to leave the ruins and how to get to the capital and through the barrier. She tells her to be safe and to spare the monsters she comes across.

She gives her a brief run down on how fights work in the underground and how to show monsters mercy. Lizette promises to spare any monsters she comes across much to Toriel's relief. And with that Lizette bids Toriel farewell and leaves the ruins. Toriel, much to her surprise, gives Lizette a quick tight hug. "Child, I do not know what happened to you on the surface, but you are safe here, you can stay here. I'll protect you, please don't go."

She's frozen in shock, her whole body stiff from the unexpected contact. She gently pulls away. "No, you cant. I have to fight my own battles, Im a big girl and I can take care of myself. I appreciate the gesture, but I have to go." Toriel nods and lets out a sad laugh, "I thought so. Please child, be safe, and good luck to you." Lizette nods and turns around walking out the ruin doors.

As the heavy doors slammed shut behind her she leaned against them. Feeling the weight of the world on her shoulders as she ran her hands through her hair roughly yanking at the curls in frustration and sadness. The warm comfort and safety she felt inside Toriel's home was torn away from her the moment that door slammed shut behind her.

It felt like a whole other world inside. Like the ruins were inside their own little protective bubble that the outside world couldn't touch.

She took a deep breath and stepped away from the door. She wrapped her arms around herself to protect herself from the cold snow. 'How on earth is it snowing underground?' She cant help but wonder.

Her boots crunching in the snow as she continues onward. The silence is almost deafening, she half expects someone to jump out at her and attack her. She continues along until she comes to a bridge with large fence like posts kind of, but not really blocking her path.

She tilts her head confused by the structure but shrugs her shoulders and carefully walks around the post and across the bridge. She continues on until she comes across a small stand where someone appeared to be taking a nap.

As quietly as she possibly could she crept closer to the sleeping figure. She could see now that it was a skeleton in a blue fur lined jacket snoring softly. She bit her lip wondering whether or not she should wake the person up. She shifted her weight from foot to foot, weighing the pros and cons.

She decides to let them sleep, after all, waking them up may only result in causing trouble for herself. She quietly creeps by, sending a million prays to whoever will listen that she doesn't wake the small skeleton up.

When she has safely passed the sleeping skeleton she lets out a sigh of relief. "Alright, lets keep going." She whispers to herself and picks up her pace, moving now at a slight jog. She keeps up a steady pace until she comes across another station, this one made of cardboard. She sees a message written on it and as she reads it she cant help but snort and laugh.

She looks around a bit for any sign of this "Great Papyrus" person but sees no one and so continues on her way. As she continues down the path however she hears a rather loud and startlingly voice. "HOLD IT RIGHT THERE!" She jumps a little in surprise and looks around for the source of the loud noise, when just as suddenly as she heard the voice she feels a humming buzz in her chest.

The feeling is strange and unexpected feeling. She's never felt such a sensation before and is highly confused. She rubs her chest, trying to get the feeling to go away. In doing so she forgot about the loud voice until it was right behind her. "YOU THERE! I'VE NEVER SEEN YOU AROUND HERE BEFORE, ARE YOU NEW HERE?"

She quickly spins around and lets out a yelp of surprise, half stepping half jumping causing her to fall backward on her butt. Thankfully the snow kept her from hurting herself. The tall skeleton looks down at her in concern and leans down to offering a hand to help her up. "WOWIE! ARE YOU OK? I DIDN'T MEAN TO SCARE YOU!"

He looks so sad and genuine that she knew he was speaking the truth. She accepted his gloved hand as he pulled her back up to standing. "Im fine, thank you," she said as she brushed the snow off her pants. She looked up, he was so tall! He had to be at least 7 feet. The humming in her chest was becoming more forceful as she stared up into his eye lights. She rubbed her chest again trying to soothe away the feeling and he tilted his head to the side, like a confused puppy as he watched her.

"ARE YOU SURE YOUR OK? IS YOUR CHEST BOTHERING YOU?" She shook her head, "Im fine. My name is Lizette, by the way." He instantly perked up "I AM THE GREAT PAPYRUS! FUTURE MEMBER OF THE ROYAL GUARD! NYEH HEH HEH!" She bit the inside of her cheek to keep from laughing. His enthusiasm was contagious to be sure.

"So then, that station I passed by was yours?" "YES IT WAS, I MUST CAPTURE A HUMAN IN ORDER TO BECOME A ROYAL GUARD. ONCE I CAPTURE THE HUMAN MY TRAINING WILL BE COMPLETE! UNDYNE WILL BE SO PROUD OF ME!" Her lips twitch upward, this skeleton was so innocent and pure. There was no way he could know what happens to the humans once their captured.

She could not sense even the smallest amounts of evil or malice coming from the being before her. No way. She cleared her throat and shifted her weight around "Uh well, was there a reason you stopped me? I was on my way to snowdin." Seeming to just remember what he was doing he hit is fist against his palm "OH RIGHT! I'VE NEVER SEEN YOU AROUND BEFORE SO I WANTED TO MAKE SURE YOU WEREN'T LOST OR ANYTHING. YOUR BRIGHT HAIR MADE YOU EASY TO SPOT AND THERE ARE NO MONSTERS THAT I KNOW OF IN SNOWDIN WITH HAIR LIKE YOURS, SO SINCE YOU WERE NEW I DECIDED THAT THE GREAT PAPYRUS SHOULD BE THE FIRST TO SAY HELLO AND WELCOME YOU."

She looked like a dear caught in the headlights and not for the first time in her life cursed her brightly colored hair. It was the bane of her existence for sure. "uh..yea.. im new! I just came from the ruins, and was passing thru. Im not familiar with the area, as a future royal guardsmen you wouldn't mind helping me out and escorting me to snowdin would you?"

Papyrus looked confused for a moment "THE RUINS? I DIDN'T KNOW ANYONE STILL LIVED THERE. THEN AGAIN SANS IS ALWAYS TALKING TO SOMEONE THROUGH THE DOOR, SO IT MAKES SENSE." She flinched as she felt her soul beating against her chest, something was wrong. Why was her soul acting this way? Its never behaved like this before! Papyrus looked back down at her in concern. "YOU DON'T LOOK SO WELL LIZETTE. HERE LET I, THE GREAT PAPYRUS, HELP YOU." He placed his hands around her waist, they were so big! She blushed a bright red as he lifted her up and placed her on his shoulder, she balanced herself against him.

This was no helping, this was definitely not helping! She yelled inside her mind as her soul slammed against her chest. Buzzing and humming with abandon. 'It was him!' Her soul was acting this way because of him! Was she wrong? Was he not as innocent as he seemed? What kind of magic had he used on her to make it act this way?

"Y-you know P-papyrus, honestly im find you dont-" "NONSENSE TINY LIZETTE, YOUR NOT FEELING WELL, AND SO I MUST HELP YOU AND TAKE YOU TO THE INN WHERE YOU CAN GET A GOOD REST AND FEEL BETTER!" She sees that trying to argue against him is pointless and just gives in. Allowing him to carry her into town. She rubs her aching chest again.

Maybe its not him. Maybe its the poison coursing through her veins. Could it finally be ready to leave her system? Maybe Papyrus was right and she just needed to rest.


	6. Ch5 The big news

**I apologize in advance about sans and his lack of puns. Im not very good with puns so i'll be googling a few for him but he's not going to have a lot. Just a few here and there.**

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**Chapter 5**

Papyrus had taken the small pink haired strange looking monster, that he was pretty sure wasn't a monster at all, to the inn and dropped her off. She looked so sad and hurt that he paid the bunny enough to allow her to stay a few nights despite the little monster's protests that, it was unnecessary. He disagreed. What kind of royal guard would he be if he didn't help out someone who very clearly wasn't feeling well.

He sat her down and patted her head and bid her farewell. He had to go check on his lazy brother, he had important news to tell him about this new mysterious pink haired monster. He could feel her gaze burning into him as he ran full speed away to his brother's station.

Once he was no longer in her sights his soul ached and throbbed but he felt to giddy and excited to pay it to much mind. "SAAAAANS! SAAAAAANS! WAKE UP LAZY BONES!" He yelled loudly startling his poor sleeping brother.

Sans rubbed his aching tail bone as he yawned and looked up at his vibrating little brother. Sans could help buy chuckle. Something very clearly had Papyrus excited, his brother was doing a very poor job of hiding it. He looked ready to absolutely burst.

"Whats up bro?" Papyrus rub his hand down his face "Sans you lazy bones how could you be sleeping at your post again brother?" Sans shrugged as he stood placing his hands in his jacket pocket. "Heh, sorry bro, you know me, im just bone tired." "Saaaans" Papyrus groaned, "no time for puns Sans! While you were sleeping a strange new monster appeared!" Sans tensed and his eye lights when out, all the while his mind going a mile a minute.

'new monster? but its to soon! Frisk isn't due to fall for another week!' "New monster eh?" Papyrus gave his brother a half hearted glare "Yes, which you would have known HAD YOU NOT BEEN SLEEPING THE JOB AGAIN!" Sans shrugged but inside he was extremely stressed and worried. This anomaly what could it mean for them, for papyrus, for Frisk. "So what about this new monster's got you all worked up?"

Papyrus was bouncing in place again and Sans couldn't help but laugh. His brother was always excitable but this was alot more than just excited energy, this was real true genuine happiness. "BROTHER! IVE FOUND MY MATE!" Papyrus all but yelled at him.

Sans' permanent smile dropped as much as it was able and he just stared him not believing what he was hearing "What was that?" "I FOUND MY MATE SANS! CAN YOU BELIEVE IT?!" "Papyrus are you sure? Absolutely sure? You've met every monster in the underground and have never felt your mate before." "Not this one Sans. Ive never met her before today." Papyrus rubs his chin thoughtfully "She says she comes from the ruins, so it would make sense that ive never met her before." 'The ruins? He cant possible mean Toriel, she's Asgore's mate.' "What's your mates name? And how are you so sure she's the one?"

"Her name is Lizette and I know its her brother, I just know it! I can feel it in my soul. Even now being away from her it throbs painfully so. I just want to be near her again and never leave her side." Sans studious his brother. It certainly sounds like a the start of the mate bond. Very similar to what he feels around Frisk, but monsters and humans CANT be mates, he knows this. Their souls aren't compatible.

So whoever was in the ruins with Toriel and that snuck past him, if they really are Papyrus' mate they most certainly are not human. So who is this mysterious monster. 'Maybe I should ask Toriel. If she's still alive.' His fist clenches in his jacket pocket.

"Well bro I cant wait to meet your new mate." Suddenly Papyrus' happy energy just drains completely out of him taking Sans by surprise. "Whoa, bro you ok?" "Sans, I think something is wrong with her." He rubs his battle armor, over where his soul is. "My soul burns, not in a good way, but like a something is wrong way. And she'd been repeatedly rubbing her chest and looked like she was in pain. Sans what if something is wrong with her? What if she's sick?! SANS WHAT DO I DO MY MATE IS SICK AND I DON'T KNOW HOW TO HELP HER!"

"Whoa whoa easy bro. Everything is going to be alright you'll see. Why don't we just go meet your new mate, and if she is sick we'll just take her to see Alphys. Im sure she'll be able to patch her right up." Papyrus seemed to take comfort in those words. "Yes, yes your right brother. BUT FIRST! I MUST GO AND MAKE HER SOMETHING DELICIOUS! MY SPAGHETTI WILL HELP CHEER HER UP AND MAKE HER FEEL GOOD AS NEW!"

"That's the spirit bro. everything will be fine. Tibia honest, i cant wait to meet you new mate. Did you take her to the inn?" He groaned at the pun but nodded "Good to know, i'll go check on her while you make the spaghetti" With that Sans took one of his famous short cuts before Papyrus could stop him. He shook his head and ran for home to make his new pate a nice big helping of his favorite dish. He was just so sure she was going to love it as much as he did.


End file.
